1. Field of the Invention
The present invention relates to arginine-containing compositions and methods for increasing blood flow using the same. Specifically, the present invention relates to arginine-containing compositions which are formulated as pharmaceutical compositions, food and beverages, animal feed, and the like. Specifically, the present invention also relates to methods using the arginine-containing compositions for increasing blood flow in the capillaries of a patient without lowering the systemic blood pressure.
2. Brief Description of the Related Art
Blood enables the transport of oxygen, nutrients, signaling molecules such as hormones, waste products, and immune cells. Namely, substances are taken up by the blood from the lungs, digestive tract, and endocrine organs, and are propelled by the heartbeat, and transported and supplied to the entire body through the capillaries. Furthermore, waste products and the like are picked up by the blood through the capillaries of the entire body and excreted from the organs, such as the lungs and kidneys. Blood also functions to retain heat in the body by circulating blood that is always maintained at a constant temperature. Thus, blood flow in the capillaries is important for maintaining the vital functions, but it can weaken when stresses occur, such as disease, infection, injury, fatigue, aging, and sudden environmental changes. For example, it is possible that weak blood flow to the brain may be related to cerebrovascular dementia and Alzheimer-type dementia, wherein the weak blood flow causes deterioration of the vital functions (U.S. Patent Application Publication No. 2002182162). Accordingly, it is important to actively increase blood flow under such conditions, so that heat retention in the body is increased and substances which actively enhance the vital functions are effectively transported by the increased blood flow.
Agents which have been used to increase blood flow include calcium antagonists, cellular respiratory activators, antispasm drugs, in vivo enzymes, and the like.
Since these agents also contain substances which reduce blood pressure and affect the blood vessels of the entire body, there is a possibility of not only increasing the blood flow in the capillaries, but also affecting the systemic blood pressure. In addition, some of the agents cause pain, such as in vivo enzymes like kallikrein. Therefore, it is strongly desirable to develop a method which is effective to increase blood flow and that is safe and easy to use.
It has been previously reported that arginine induces vasodilation. As its mode of action, it has been reported that vascular endothelial cells which contain nitric monoxide synthetases synthesize nitric monoxide from arginine, which causes vasodilation. Externally administered arginine immediately synthesizes nitric monoxide, and this action also produces vasodilation. However, dietary-derived arginine does not usually have the same effect (Japanese Patent Unexamined Publication No. 2004-262878).
Though the actions of arginine when ingested has been widely reported, it has been conventionally thought that vasodilation caused by arginine results in a lowering of blood pressure as well as an increase in blood flow. For example, it has been reported that, when 30 g or 6 g of arginine was parenterally administered to human beings having an average weight of 78 kg, the 30 g of arginine lowered blood pressure and vascular resistance, while the 6 g of arginine did not cause either effect (British Journal of Clinical Pharmacology 1998; 46: 489-497. In addition, other methods for increasing blood flow using arginine have been reported. However, in every such case, the dosage of arginine is very high, or the arginine must be combined with other compositions which alone can act to increase blood flow, such as polyphenols (Anesthesiology 1994; 80: 1320-1327, U.S. Patent Application Publication No. 2002/0182162, Japanese Patent Unexamined Publication No. 2004-262878). Therefore, increasing blood flow using solely arginine without lowering blood pressure has never been reported.